Let me tell you why.
If I'm trying to make a good impression and I only have a limited amount of space or time to do so, I would think it's important to have my act together. While I certainly understand and can forgive nervousness or lack of polish, when I come across sloppy errors or blatant incompetence, it's the delete file for you. I have a very limited amount of time and I need to focus meeting goals. I'll give you an example of something that put me over the edge.
An email arrived in my inbox with the subject: Targeted Emailing List
I thought: "Okay, I'm not directly responsible for email marketing, but this might be interesting for some related reason."
I was quickly disavowed of that notion when I read the body of the email, which began:
Dear Customer: [emphasis not even added - they were dumb enough to make it bold]
We are a list compiler and a dominant player in the List Business Industry with over 40 Million B2B contacts and 200 Million B2C contacts. We have all varieties of business records that come with complete contact details including working business email addresses.
Aside from the annoyance of being called "Customer," (which I'm not), the very service they're selling is "complete contact details" of 200 million contacts. I guess I didn't make it into the database.
If you're going to convince someone of your ability, please be sure you've demonstrated it effectively. Physician, heal thyself.
Have you had any similar experiences?